Recombination batteries (i.e. batteries in which the hydrogen and oxygen recombine to form water) tend to have separators of microporous glass fibre in which the acid electrolyte is fully absorbed. The separator material is extremely delicate and the group has to be loaded into the battery box in a compressed state (and retained in that state by the box) in order to ensure that the electrolyte is in active contact with the places.
It will readily be appreciated that there are significant difficulties in inserting the compressed group into the battery box cell when that cell is substantially the same size without damaging the separators.
There are also problems in transferring such groups from the processing jig boxes, because the walls in the jig boxes which apply the compression can mark the separators if they do not act over the full separator surface. Accordingly attempts have been made to load the groups directly from the jig box by providing guides on the ends of the jig box walls. However, these guides can only extend partially across the width of the battery cell, because space must be allowed for the transverse supports on which the group elements sit when the jig box is being loaded. The result is that the unguided portions of the groups snag on the box wall.